scholarly journals A Review on Potential Issues and Challenges in MR Imaging

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Srinivasan Kathiravan ◽  
Jagannathan Kanakaraj
Keyword(s):  
Mr Imaging ◽  
High Field ◽  
Processing System ◽  
Imaging Systems ◽  
7 Tesla ◽  
Rf Coils ◽  
Resonance Imaging ◽  
Data Processing System ◽  
Ultra High Field ◽  
Noninvasive Technique

Magnetic resonance imaging is a noninvasive technique that has been developed for its excellent depiction of soft tissue contrasts. Instruments capable of ultra-high field strengths, ≥7 Tesla, were recently engineered and have resulted in higher signal-to-noise and higher resolution images. This paper presents various subsystems of the MR imaging systems like the magnet subsystem, gradient subsystem, and also various issues which arise due to the magnet. Further, it also portrays finer details about the RF coils and transceiver and also various limitations of the RF coils and transceiver. Moreover, the concept behind the data processing system and the challenges related to it were also depicted. Finally, the various artifacts associated with the MR imaging were clearly pointed out. It also presents a brief overview about all the challenges related to MR imaging systems.

scholarly journals P.063 Stereotactic targeting of hippocampal substructures using ultra-high field magnetic resonance imaging: Feasibility study in patients with epilepsy

2018 ◽  
Vol 45 (s2) ◽  
pp. S32-S33
Author(s):  
JC Lau ◽  
J DeKraker ◽  
KW MacDougall ◽  
H Joswig ◽  
AG Parrent ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Dentate Gyrus ◽  
High Field ◽  
Longitudinal Axis ◽  
The Body ◽  
7 Tesla ◽  
Resonance Imaging ◽  
Ultra High Field

Background: The hippocampus can be divided longitudinally into the head, body, and tail; and unfolded medial-to-laterally into the subiculum, cornu ammonis (CA) sectors, and the dentate gyrus. Ultra-high field (≥ 7 Tesla; 7T) magnetic resonance imaging (MRI) enables submillimetric visualization of these hippocampal substructures which could be valuable for surgical targeting. Here, we assess the feasibility of using 7T MRI in conjunction with a novel computational unfolding method for image-based stereotactic targeting of hippocampal substructures. Methods: 53 patients with drug-resistant epilepsy were identified undergoing first-time implantation of the hippocampus. An image processing pipeline was created for computationally transforming post-operative electrode contact locations into our hippocampal coordinate system. Results: Of 178 implanted hippocampal electrodes (88 left; 49.4%), 25 (14.0%) were predominantly in the subiculum, 85 (47.8%) were in CA1, 23 (12.9%) were in CA2, 18 (10.1%) were in CA3/CA4, and 27 (15.2%) were in dentate gyrus. Along the longitudinal axis, hippocampal electrodes were most commonly implanted in the body (92; 51.7%) followed by the head (86; 48.3%). Conclusions: 7T MRI enables high-resolution anatomical imaging on the submillimeter scale in in vivo subjects. Here, we demonstrate the utility of 7T imaging for identifying the relative location of SEEG electrode implantations within hippocampal substructures for the invasive investigation of epilepsy.

scholarly journals The Amsterdam Ultra-high field adult lifespan database (AHEAD): A freely available multimodal 7 Tesla submillimeter magnetic resonance imaging database

NeuroImage ◽  
2020 ◽  
Vol 221 ◽  
pp. 117200 ◽  
Author(s):  
Anneke Alkemade ◽  
Martijn J Mulder ◽  
Josephine M Groot ◽  
Bethany R Isaacs ◽  
Nikita van Berendonk ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
High Field ◽  
7 Tesla ◽  
Resonance Imaging ◽  
Ultra High Field ◽  
Adult Lifespan

Susceptibility weighted magnetic resonance imaging of cerebral cavernous malformations: prospects, drawbacks, and first experience at ultra–high field strength (7-Tesla) magnetic resonance imaging

2010 ◽  
Vol 29 (3) ◽  
pp. E5 ◽  
Author(s):  
Philipp Dammann ◽  
Markus Barth ◽  
Yuan Zhu ◽  
Stefan Maderwald ◽  
Marc Schlamann ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
High Field ◽  
Susceptibility Weighted Imaging ◽  
Cerebral Cavernous Malformations ◽  
Resonance Imaging ◽  
High Field Strength ◽  
Ultra High Field ◽  
Cavernous Malformations

High-resolution susceptibility weighted MR imaging at high field strength provides excellent depiction of venous structures, blood products, and iron deposits, making it a promising complementary imaging modality for cerebral cavernous malformations (CCMs). Although already introduced in 1997 and being constantly improved, susceptibility weighted imaging is not yet routine in clinical neuroimaging protocols for CCMs. In this article, the authors review the recent literature dealing with clinical and scientific susceptibility weighted imaging of CCMs to summarize its prospects and drawbacks and provide their first experience with its use in ultra–high field (7-T) MR imaging.

scholarly journals The Travelling-Wave Primate System: A New Solution for Magnetic Resonance Imaging of Macaque Monkeys at 7 Tesla Ultra-High Field

PLoS ONE ◽  
2015 ◽  
Vol 10 (6) ◽  
pp. e0129371 ◽  
Author(s):  
Tim Herrmann ◽  
Johannes Mallow ◽  
Markus Plaumann ◽  
Michael Luchtmann ◽  
Jörg Stadler ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
High Field ◽  
Travelling Wave ◽  
7 Tesla ◽  
Resonance Imaging ◽  
Ultra High Field ◽  
Macaque Monkeys ◽  
System A ◽  
Primate System

scholarly journals Multiscale Parameter Estimation (msPE) of QRS complexes distorted by magnetohydrodynamic effects at 7 Tesla

2019 ◽  
Vol 5 (1) ◽  
pp. 365-367
Author(s):  
Nicolai Spicher ◽  
Markus Kukuk ◽  
Stefan Maderwald ◽  
Mark E. Ladd
Keyword(s):  
Parameter Estimation ◽  
High Field ◽  
Gaussian Function ◽  
7 Tesla ◽  
Qrs Complex ◽  
Resonance Imaging ◽  
Ultra High Field ◽  
Algebraic Expressions ◽  
Acceptable Range ◽  
Future Work

AbstractDuring ultra-high-field magnetic resonance imaging, the acquisition of electrocardiography is impeded by artifacts. This poses a challenge in examinations where the QRS complex is used as a trigger for activating image acquisition. In this work, we customize a framework for multiscale parameter estimation for processing electrocardiography signals acquired inside and outside an ultra-high-field scanner bore: The parameters of a QRS complex modeled by a Gaussian function were estimated using scale-dependent algebraic expressions for 600 heartbeats from three subjects. Sensitivity ≥ 94% and accuracy ≤ 5ms in each experiment indicate feasibility of this approach, and, additionally, run time is within the acceptable range for triggering latency in the majority of cases. Hence, we see a real-time implementation as an avenue for future work.

scholarly journals Forging a path to mesoscopic imaging success with ultra-high field functional magnetic resonance imaging

2020 ◽  
Vol 376 (1815) ◽  
pp. 20200040 ◽  
Author(s):  
Kimberly B. Weldon ◽  
Cheryl A. Olman
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
High Field ◽  
7 Tesla ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Ultra High Field ◽  
Spatial Specificity ◽  
The Impact

Functional magnetic resonance imaging (fMRI) studies with ultra-high field (UHF, 7+ Tesla) technology enable the acquisition of high-resolution images. In this work, we discuss recent achievements in UHF fMRI at the mesoscopic scale, on the order of cortical columns and layers, and examine approaches to addressing common challenges. As researchers push to smaller and smaller voxel sizes, acquisition and analysis decisions have greater potential to degrade spatial accuracy, and UHF fMRI data must be carefully interpreted. We consider the impact of acquisition decisions on the spatial specificity of the MR signal with a representative dataset with 0.8 mm isotropic resolution. We illustrate the trade-offs in contrast with noise ratio and spatial specificity of different acquisition techniques and show that acquisition blurring can increase the effective voxel size by as much as 50% in some dimensions. We further describe how different sources of degradations to spatial resolution in functional data may be characterized. Finally, we emphasize that progress in UHF fMRI depends not only on scientific discovery and technical advancement, but also on informal discussions and documentation of challenges researchers face and overcome in pursuit of their goals. This article is part of the theme issue ‘Key relationships between non-invasive functional neuroimaging and the underlying neuronal activity’.

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